Selective copper extraction by multi-modified mesoporous silica material, SBA-15

Area of Science:

• Materials Science
• Environmental Chemistry
• Chemical Engineering

Background:

• Selective copper recovery from wastewater is crucial for environmental protection and economic value.
• Existing adsorbents often struggle with selectivity in complex heavy metal mixtures.
• Mesoporous silica materials offer tunable properties for adsorption applications.

Purpose of the Study:

• To synthesize and characterize novel amine-grafted mesoporous silica (SBA-15-NH2) and manganese-loaded amine-grafted mesoporous silica (Mn-SBA-15-NH2) adsorbents.
• To evaluate the selective copper (Cu) adsorption capacity and performance of these materials from wastewater.
• To investigate the influence of pH, adsorption kinetics, and isotherms on Cu removal.

Main Methods:

• Fabrication of SBA-15-NH2 and Mn-SBA-15-NH2 using KMnO4 and 3-aminopropyltriethoxysilane.
• Characterization using XRD, BET surface area analysis, BJH pore size distribution, TEM, and XPS.
• Adsorption experiments conducted in single and mixed heavy metal solutions at varying pH.
• Analysis of adsorption equilibrium using Langmuir and Freundlich models and kinetics using LDFA and PDM.

Main Results:

• Mn-SBA-15-NH2 exhibited a high Cu adsorption capacity of 2.08 mmol/g.
• Excellent selectivity for Cu was observed in mixed heavy metal solutions (2.01 mmol/g), maintaining 96% of single-solution capacity.
• Optimal adsorption occurred at pH 5, facilitating strong chelating bonds.
• Adsorption followed Langmuir and Freundlich isotherms and LDFA and PDM kinetics.
• The adsorbent maintained 90% capacity after multiple adsorption-desorption cycles.

Conclusions:

• Mn-SBA-15-NH2 is a highly effective and selective adsorbent for copper recovery from wastewater.
• The material demonstrates robust regeneration and reuse capabilities.
• This adsorbent presents a promising solution for mitigating environmental pollution and enabling economic recovery of copper.